At present, there are many types of micro sprayers in the market. These micro sprayers atomize and spray the liquid in the container by pressing the lever or head cap. The working principle is: piston moves in bump body, which make air flow and lower the pressure inside the bump body, while pressure outside bump body is unchanged. It produces pressure difference inside and outside the bump body. Take advantage of pressure difference, to lead liquid out from bump body, and the liquid will be instantaneously atomized when encountering high speed flow. It is an application of Bernoulli's principle: for a same liquid, high flow corresponds to low pressure; low flow corresponds to high pressure. These sprayers have been widely used in flower planting, hair salon and cosmetology, etc. wherein, some micro sprayers with press head cap are mainly used to cosmetology industry as perfume sprayer, which is also called perfume bump. To prevent perfume and spring from being affected due to chemical reaction between metal spring of bump body and liquid perfume, some perfume bumps adopt external spring. E.g. “press perfume sprayer with external spring and its dual pressing method” with application number of 201410193366.5 and application announcement date of 2015 May 7 disclosed by Chinese patent literature. Piston, valve needle, inner stopper, long spring, short spring and valve rod form the valve needle unit of the sprayer. The said valve needle unit, bump body and glass bulb form bump body unit. Alumina press cap, spray chip and head cup form bump head unit. The key point is that the said valve needle of valve needle unit sets into piston with interference, and piston sets into inner stopper with interference; the inner stopper snap-fit with bump body, and the valve needle snap-fit with valve rod. Long spring is located between inner stopper and valve rod, and short spring is located between valve rod and valve needle. The long spring is equipped in external diameter of short spring. In the same time, valve needle unit realizes dual pressing through long spring and short spring, and limits the piston by stepped terminal angle of inner diameter of bump body. Although the spring of the said structure has realized external spring, and prevent the perfume from being effected by spring, some deficiencies are existed: weak stability of structure of the external spring, inconvenient assembly and production, and complicated process.